The present invention relates to semiconductor fabrication, and more specifically, to controlling etch of layers during semiconductor fabrication.
An organic planarization layer (OPL) is mostly used for back end of line (BEOL) processes such as tri-layer for patterning, but also for planarization layer or etch back. Commonly, the OPL is etched entirely, and laser spectrometry reflectometry (LSR) or optical emission spectroscopy (OES) can be used for endpoint detection of the OPL etch. It is generally easy to detect removal of an entire layer because different materials provide a clear transition in plasma color and in reflected wavelength.